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A new Earth-viewing satellite sensor that can observe both natural and artificial sources of visible light at night is providing a treasure trove of high-quality information for scientists, meteorologists, firefighters and city planners. The Day Night Band (DNB) sensor is so sensitive it can measure the glow of a single streetlamp from its vantage point 800 kilometers above. With moonlight, the DNB can observe clouds, snow and sea ice in almost as much precision as conventional daytime observations....

A study participant walks briskly on a treadmill, video cameras recording his every move, when a 35-pound metal block suddenly appears in his path. Special eyeglasses prevent him from seeing it, and he stumbles, lurching forward—until he is caught by a safety harness. One trip down, dozens more to go. Researchers developed the treacherous treadmill to study how people regain their footing after tripping. They knew this usually means taking an exaggerated step that allows the central nervous system to reorient the body’s center of gravity above firm footing, says Michael Goldfarb, a mechanical engineer at Vanderbilt University and co-author of the treadmill study....

By Sarah N. Lynch and Bill Berkrot A pediatric doctor in Alabama had to scramble to find a less expensive supply of a lifesaving drug to treat an infant who was suffering from a parasitic infection. In Utah, a hospital has been forced to change the way it stocks a drug critical to treating heart patients after the cost skyrocketed from $440 to $2,700 a vial. These are two of the stories a U....

On March 6 NASA’s Kepler space telescope embarked on a four-year mission to discover Earth-like planets in the Milky Way. Like its predecessor, the French-led COROT mission launched in December 2006, Kepler will monitor a selection of stars for temporary decreases in brightness. One dip could mean anything, probably just a blip in the star’s energy output; a second dip would still signify relatively little; a third dip, occurring after the same time interval as that between the first and second, would seem highly provocative; and a fourth dip after an identical interval would almost certainly mean that a planet is on an orbit that carries it directly between the star and us....

Editor’s note: The following essay is reprinted with permission from The Conversation, an online publication covering the latest research. In the last few decades, lasers have become an important part of our lives, with applications ranging from laser pointers and CD players to medical and research uses. Lasers typically have a very well-defined direction of propagation and very narrow and well-defined emission color. We usually imagine a laser as an electrical device we can hold in our hands or as a big box in the middle of a research laboratory....

Chris Wiggins, an associate professor of applied mathematics at Columbia University, offers this explanation. A patient goes to see a doctor. The doctor performs a test with 99 percent reliability–that is, 99 percent of people who are sick test positive and 99 percent of the healthy people test negative. The doctor knows that only 1 percent of the people in the country are sick. Now the question is: if the patient tests positive, what are the chances the patient is sick?...

If you’re old enough, you might remember a game show called Let’s Make a Deal hosted by a guy named Monty Hall. The show was a bit before my time, but one of the games from the show—or at least a variant of it—has stood the test of time to become one of the most debated math brain teasers ever. In honor of the show’s host, it’s called the Monty Hall problem....

Far from being a solely quantum mechanical phenomenon, interference occurs with all kinds of waves, including water waves and sound waves. Interference is the process in which two or more waves of the same kind come together, and they can add so as to reinforce one another or they can combine so as to cancel one another. For example, the crests of two water waves can add together to give a very large wave, or the crests of one wave can combine with the troughs of another to give a much smaller wave....

We can all be grateful that pancreatic cancer is pretty rare—accounting for about 3 percent of all cancers. Its toll, however, is another story. Five years ago it was the fourth-leading cause of cancer deaths in the U.S. Today it’s number three and expected to soon overtake colon cancer for the number-two spot, right behind lung cancer. Even more frightening, this lethal condition is becoming more common. In the U.S., its incidence has crept upward by about 0....

The year is 2030. Gene therapy to insert the DNA sequence for dystrophin has been approved by regulators and is commonly used in children with Duchenne muscular dystrophy (DMD), a disorder linked to the X chromosome. Evidence shows that the intervention increases muscle mass in anyone who receives it. The treatment is widely available, but very expensive. Alex, a slender adolescent, walks into a physician’s office, accompanied by well-to-do parents. Alex does not have DMD, but wants to be stronger....

Since its passage in 1983, the Orphan Drug Act (ODA) has led to the approval of 357 drugs for rare diseases and a pipeline of more than 2,100 additional products. Before the ODA, just 10 such drugs existed. Considering that some 7,000 rare diseases affect 20 million to 30 million Americans, federal overseers and patient advocates are anxious to ramp up efforts even more. But finding a way to give the act a second wind is kicking up dust both scientific and financial....

Nerve cells in our limbs can regenerate after injury, but neurons in the central nervous system, which includes the brain and spinal cord, cannot. Figuring out why this is the case is critical to helping brain and spinal cord injuries heal. A study published in the January 26 issue of Neuron may offer a promising solution. Not only did the researchers, Rachid El Bejjani and Marc Hammarlund of Yale University, identify what appears to be a key chemical regulator of neuron repair, but drugs that target this regulator already exist, making the path to clinical treatments easier....

By Elie Dolgin of Nature Medicine magazine Men with advanced prostate cancer now have another treatment option, thanks to the approval August 31 by the U.S. Food and Drug Administration (FDA) of a pill that blocks androgen-receptor signaling and prolongs patient survival. “To see activity in a post-hormone treated, post-chemotherapy treated prostate cancer population with a drug that doesn’t have myelosuppression [a decrease in blood cell production] and does has a very favorable safety profile is extremely exciting,” says Howard Scher, a prostate cancer specialist at the Memorial Sloan-Kettering Cancer Center in New York....

Ice-road truckers may become an endangered species as climate change intensifies in the Arctic, concludes a new study that examines how rising temperatures will alter the transportation mix in the far north. Researchers at the University of California, Los Angeles, say that by midcentury, warming will significantly limit the areas suitable for constructing temporary roads each winter. The season for using such roads, key transport routes for cargo, will also shorten....

Editor’s Note: This article is part of a special report on the Top 10 Emerging Technologies of 2016 produced by the World Economic Forum. The list, compiled by the Forum’s Meta-Council on Emerging Technologies, highlights technological advances its members, including Scientific American Editor in Chief Mariette DiChristina, believe have the power to improve lives, transform industries and safeguard the planet. It also provides an opportunity to debate any human, societal, economic or environmental risks and concerns that the technologies may pose prior to widespread adoption....

SAN FRANCISCO – Soon after Gov. Arnold Schwarzenegger (R) took office in 2003, he set in motion a campaign promise to build, by 2010, a “hydrogen highway” composed of 150 to 200 fueling stations spaced every 20 miles along California’s major highways. Schwarzenegger’s “Vision 2010” plan promised that every California motorist would have access to hydrogen fuel by the end of the decade. He has since repeatedly mentioned the highway in a standard stump speech on his environmental accomplishments....

For thousands of years people have played with magic squares—arrays of distinct numbers whose rows, columns and diagonals add to the same total.* A simple 3-by-3 array that sums to 15 every which way appears on the back of a turtle in the legend of Lo Shu, a Chinese tale from 650 B.C. Medieval mathematicians in the Middle East and India studied magic squares of varying sizes and Albrecht Dürer included a 4-by-4 magic square in his famous engraving, Melencolia I, in 1514....

Climate change has doubled the number of extreme-risk days for California wildfires, according to research released yesterday. An analysis led by Stanford University found that temperatures rose about 1.8 degrees Fahrenheit statewide while precipitation dropped 30% since 1980. That doubled the number of autumn days—when fire risk is highest—with extreme conditions for the ignition of wildfires. “That’s a really big increase over a relatively short period of time that can be attributed directly to the changes in climate,” said Daniel Swain, a climate scientist at UCLA and one of the study’s authors....

Sigmund Freud’s views on the meaning of dreams formed the core of his theory of mental functioning. Mark Solms and others assert that modern science is now validating Freud’s conception of the mind. But similar scientific investigations show that major aspects of Freud’s thinking are probably erroneous. For Freud, the bizarre nature of dreams resulted from an elaborate effort of the mind to conceal, by symbolic disguise and censorship, the unacceptable instinctual wishes welling up from the unconscious when the ego relaxes its prohibition of the id in sleep....

Physicists have devised a way to take pictures using light that has not interacted with the object being photographed. This form of imaging uses pairs of photons, twins that are ‘entangled’ in such a way that the quantum state of one is inextricably linked to the other. While one photon has the potential to travel through the subject of a photo and then be lost, the other goes to a detector but nonetheless ‘knows’ about its twin’s life and can be used to build up an image....